1. Field of the Invention
This invention relates to underground pipe and sprinkler supports, and in particular to supports for in-ground pop-up sprinklers such as commonly used in commercial irrigation systems for parks, golf courses, etc.
2. Brief Statement of the Prior Art
The in-ground pop-up sprinklers which are commonly used in commercial irrigation systems, particularly for golf courses, have pop-up sprinklers which are contained in cylindrical housings that are mounted with their tops flush with the ground surface. It is desirable that the exposed area of the sprinkler is minimal to reduce the unsightliness and obstruction of the installation. The sprinkler heads are commonly installed on risers which are connected to subterranean water supply lines, such as water mains or laterals by swing joints which are formed with a combination of elbows and couplings which provide flexibility to the installation, permitting it to rise and fall with expansion and contractions of the surrounding earth.
A common problem which plagues such installations, particularly in sandy or loose shale soil, is the tendency of the sprinkler installations to migrate downwardly into the soil. This obstructs the sprinkler operation and also creates a hazardous condition and unsightly appearance. The problem is pointed out in U.S. Pat. No. 5,037,238 which discloses a retrieval system to restore sunken sprinklers to their original position, flush with the ground surface. This approach, however, does not alleviate or eliminate the problem; it only provides a method to restore sunken sprinklers.
There have been various discs and plates proposed for use with in-ground sprinklers, such as a thick plastic disc which is mounted entirely at the ground surface in U.S. Pat. No. 3,904,120. Another similar device is shown in U.S. Pat. No. 5,253,952 in which a large diameter hollow-form disc is placed about the sprinkler head. A similar device is shown in U.S. Pat. No. 5,222,669 in which a large diameter disc is placed about a pop-up sprinkler head. This does not provide the best support, as the top soil is the most unstable. Further, the large diameter discs are exposed at the ground surface and this is objectionable in commercial installations such as golf courses, parks and the like.
U.S. Pat. No. 4,765,541 discloses a housing for a drip irrigation emitter which is generally tubular with a top planer closure and a base flange. This housing is substantially hollow with apertures at its base to permit egress of the irrigation water.
Various techniques have been used to stabilize land drains in soil. U.S. Pat. No. 1,071,253 discloses a subterranean inverted bell housing in which the housing forms a water collector. A similar structure is shown in U.S. Pat. No. 1,140,903. U.S. Pat. Nos. 4,475,844 and 4,553,876 disclose supports for surface drains which have a generally conical disc with a central opening that slidably receives a drain pipe. This disc only provides lateral support as the drain pipes are freely slidable vertically in the supports.
Another commonly related problem is the instability of the various lateral water supply pipes of a subterranean system. Commonly, these pipes are laid in ditches several feet beneath the surface of the soil, usually on a porous base of gravel, sand or aggregate fill. These pipes often settle, causing leaks and ruptures, particularly during earthquakes or any other abrupt shifting of the ground.